[Taxacom] Schwartz and Grehan (2009) cited on Dinosaur Mailing List

Robinwbruce at aol.com Robinwbruce at aol.com
Wed Sep 14 06:17:56 CDT 2011


John,
 
Despite the risk of clouding already muddy waters, I thought I would throw  
in my 2 cents worth.
 
Indeed, how equivalent are genetic information systems, and  
morphogenetic/epigenetic order systems? Are they sufficiently similar in their  natures to 
make comparisons between them useful or instructive? The former seem  to be 
largely decoupled from organismic time/space, and represent a  linear 
informational continuity of life (pre formation, dare one say?); the  latter are 
intrinsic (immanent?) to the time/space germination of  biological order 
(epigenesis, dare one say?). Information v. process?
 
Perhaps the former resolve by a calculus of classes; the  latter, by a 
calculus of individuals; and perhaps there can be no  ready equivalence between 
them.
 
Robin
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
In a message dated 9/13/2011 3:30:53 P.M. GMT Daylight Time,  
jgrehan at sciencebuff.org writes:

The  problem with the various molecular patterns being congruent is that
the  congruence may not necessarily lend any greater weight if they are
based on  the same kinds of assumptions. As for morphology (really
morphogenetics) it  is not a 'single' source, but multiple developmental
genetic  systems.

With respect to the Yunis and Prakash paper, Schwartz (1987)  noted the
following:

Humans and orangutan have in common chromosome  5, a particular pattern
of 12 and 19, and most of Yq, the lower extent of  the Y (male sex)
chromosome. 

The chimpanzee and the gorilla also  share four apparently homologous
chromosomes - another configuration of 12,  19, 20, and 21 - but with
different banding patterns from those which  distinguish chromosomes 12
and 19 in humans and orangutans.

Without  at least the gibbon for comparison, one cannot begin to get any
insight  into which banding pattern on any given chromosome is derived
for the  hominoids. But we are left with the tantalizing hint of support
for the  unity of humans and orangutans as well as for chimpanzees  and
gorilla

John Grehan

-----Original Message-----
From:  Kim van der Linde [mailto:kim at kimvdlinde.com] 
Sent: Tuesday, September 13,  2011 10:06 AM
To: John Grehan
Cc: taxacom at mailman.nhm.ku.edu
Subject:  Re: [Taxacom] Schwartz and Grehan (2009) cited on Dinosaur
Mailing  List

John,

I have been working on drosophilid phylogenies for a  while, and I have 
seen the whole range of sources that have been used.  When I see plain 
basepair phylogeny be congruent with chromosome banding  phylogenies, 
being congruent with isozyme based phylogenies being  congruent with 
indel patterns being congruent with gene duplication  patterns being 
congruent with internal morphology, I am convinced that the  mismatches 
in the external morphology are not going to be better than the  rest. I 
see a similar pattern with the great ape discussion. The DNA  phylogeny 
is congruent with chromosome banding patterns for example. If  you want 
to show that several sources of information are all incorrect and  the 
morphological evidence is superior, you have to show how those  
similarities arose to the point that they are misleading for the actual  
family history. Yes, when you have multiple sources claiming one thing  
and one source the opposite, it becomes an extraordinary claim requires  
extraordinary evidence situation.

Just one example: Yunis, J. J.,  Prakash, O., The origin of man: a 
chromosomal pictorial legacy. Science,  Vol 215, 19 March 1982, pp. 1525 
- 1530

Kim


On 9/13/2011  9:49 AM, John Grehan wrote:
> It's a bit meaningless to say that  "extraordinary claims require
> extraordinary evidence". What is the  extraordinary claim here? Is it
any
> less extraordinary to assert  that base sequences provide the answer
than
> anything  else?
>
> As for the chromosomal rearrangement patterns, what  sources are your
> referring to and what evidence  specifically?
>
> John Grehan
>
> -----Original  Message-----
> From: taxacom-bounces at mailman.nhm.ku.edu
>  [mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Kim van der
>  Linde
> Sent: Tuesday, September 13, 2011 9:41 AM
> To:  taxacom at mailman.nhm.ku.edu
> Subject: Re: [Taxacom] Schwartz and Grehan  (2009) cited on Dinosaur
> Mailing List
>
> Well, I always  liked the chromosomal rearrangement patterns the best
as
> evidence  for human-chimp, especially chromosome two that is  most
similar
>
> to the chimpanzee chromosomes. Really,  parallelisms are so common that
> you need far more than some  morphological similarities to be able to
> reject the results of many  thousands of base-pairs, in-dels,
chromosome
> inversions etc.  Extraordinary claims require extraordinary evidence.
>
>  Kim
>
> On 9/12/2011 11:26 PM, Kenneth Kinman wrote:
>>  Dear All,
>>          I was catching up on  postings at the DML (Dinosaur Mailing
> List),
>> and one last  week caught my eye.  It cites the paper by Schwartz and
>>  Grehan (2009) challenging the exclusivity of a supposed  chimp-hominid
>> clade.  Although the poster has reservations  about the paper's
>> conclusions, he does make some interesting  observations (as does Greg
>> Paul, whose posting he is responding  to).  However, one thing that he
>> fails to point out is that  Schwartz and Grehan, 2009, do not produce
>> even a single molecular  character to support their proposed
>> orangutan-hominid clade, which  in my mind is it biggest shortcoming.
>>         Therefore, if Schwartz and Grehan cannot produce  any
molecular
>> evidence to support an orangutan-hominid clade,  and the molecularists
>> cannot produce convincing morphological  evidence for a chimp-hominid
>> clade, then I still feel that  hominids most like did not exclusively
>> clade with either of them,  but that they are sister group to a
>> chimp-gorilla  clade.
>>          It seems that  symplesiomorphies are relatively easy to find
> among
>> greats  apes, but finding true synapomorphies (molecular or
>> morphological)  for its subclades is no easy matter.  I have little
>  hope
>> of relevant fossil finds shedding much light on the debate  anytime
> soon,
>> but whole genomes (especially certain LINES  contained therein) will
> soon
>> make considerable progress in  resolving this debate.  Anyway, for the
>> DML postings (for  what they are worth), see the weblink below.
>>       -----------Ken Kinman
>>
>>  http://dml.cmnh.org/2011Sep/msg00030.html
>>
>>
>>
>>  _______________________________________________
>>
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>>
>

--  
http://www.kimvdlinde.com

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